The A2 Birdcage flash hider is the old standard by which modern muzzle devices are measured. Combining excellent flash suppression and muzzle climb reduction with a minimal dust signature and blast, the A2 is easily one of the best standard muzzle devices available on the market. Caliber: 5.56/.223 Thread Pitch: 1/2 x 28 TPI Overall Length- 1.750" Weight- 1.92oz Heat Treated for strength and durability Phosphate Coated for corrosion resistance Milled flats for easy installation